Lawrence Owusu

Galectin-3 in cancer

Galectin-3 (Gal-3) plays important roles in cell proliferation, adhesion, differentiation, angiogenesis and apoptosis in normal and pathologic tissues. Accumulated evidences indicate that Gal-3 is closely involved in tumor cell transformation, migration, invasion and metastasis. In this review, the associations of the expression and localization of Gal-3 as well as its potential action mechanism in tumorigenesis in a variety of cancers were summarized and concluded. Gal-3 is gaining its attraction as a potential new biomarker for the diagnosis, treatment and prognosis of certain tumors.

Fermentation supernatants of Lactobacillus delbrueckii inhibit growth of human colon cancer cells and induce apoptosis through a caspase 3‑dependent pathway

Probiotic bacteria are known to exert a wide range of beneficial effects on their animal hosts. Therefore, the present study explored the effect of the supernatants obtained from Lactobacillus delbrueckii fermentation (LBF) on colon cancer. The results indicated that the proliferation of LBF solution-treated colon cancer SW620 cells was arrested and accumulated in the G1 phase in a concentration-dependent manner. The LBF solution efficiently induced apoptosis through the intrinsic caspase 3-depedent pathway, with a corresponding decreased expression of Bcl-2. The activity of matrix metalloproteinase 9, which is associated with the invasion of colon cancer cells, was also decreased in the LBF-treated cells. In conclusion, the results demonstrate the antitumor effect of LBF in vitro and may contribute to the development of novel therapies for the treatment of colon cancer.

Epigallocatechin‑3‑gallate induces the apoptosis of hepatocellular carcinoma LM6 cells but not non‑cancerous liver cells

Epigallocatechin-3-gallate (EGCG) is a constituent of green tea and has been associated with anticancer activity. In the present study, the inhibitory effect of EGCG on human hepatocellular cancer cells was examined by cell viability assay, in vitro apoptosis assay and cell cycle analysis. In addition, gene expression was measured to elucidate the molecular mechanisms of action of EGCG by mitochondrial membrane potential (MMP) determination and western blot analysis. We demonstrated that EGCG induced apoptosis, decreased mitochondrial membrane potential and promoted G0/G1 phase cell cycle arrest of HCCLM6 cells but not that of non-cancerous liver cells (HL-7702). The EGCG-induced apoptosis of HCCLM6 cells was associated with a significant decrease in Bcl-2 and NF-κB expression. In addition, the expression of Bax, p53, caspase-9 and caspase-3 increased, and cytochrome c was released. These results suggest that EGCG inhibits the progression of cancer through cytocidal activity and that it is a potential therapeutic compound for hepatocellular carcinoma (HCC).

Prediction of metabolic syndrome among postmenopausal Ghanaian women using obesity and atherogenic markers.

BackgroundMetabolic syndrome (MetS) is an important health problem which puts individuals at risk for cardiovascular diseases and type 2 diabetes as well as obesity-related cancers such as colon and renal cell in men, and endometrial and oesophageal in women.ObjectiveThis study was aimed at examining how obesity indicators and related determinants influence metabolic syndrome, and how the factors can be used to predict the syndrome and its cut-offs in postmenopausal Ghanaian women.MethodsTwo hundred and fifty (250) Ghanaian subjects were involved in the study with one hundred and forty-three (143) being premenopausal women and one hundred and seven (107) postmenopausal women. The influence of traditional metabolic risk factors including high blood pressure, dyslipidemia and glucose intolerance on obesity and atherogenic indices i.e. body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), Waist-to-thigh ratio (WTR), waist-to-height ratio (WHtR), high density lipoprotein cholesterol to total cholesterol ratio (HDL-C/TC), high density lipoprotein cholesterol to low density lipoprotein ratio (HDL-C/LDL-C) and triglyceride to high density lipoprotein cholesterol ratio (TG/HDL-C) were identified according to the Harmonization (H_MS) criterion.ResultsThe predominant anthropometric marker that significantly influence metabolic risk factors among the pre- and postmenopausal women was waist-to-hip ratio (premenopausal: p- 0.004, 0.026 and 0.002 for systolic blood pressure (SBP), fasting blood glucose (FBG) and HDL-C; postmenopausal: p-0.012, 0.048, 0.007 and 0.0061 for diastolic blood pressure (DBP), FBG, triglyceride (TG) and high density lipoprotein cholesterol (HDL-C) respectively). Using the receiver operating characteristic (ROC) analysis, the area under the curve for WC, WHR, TG/HDL-C and HDL-C/TC among postmenopausal women were estimated at 0.6, 0.6, 0.8 and 0.8 respectively. The appropriate cut-off values for WC, WHR, TG/HDL-C and HDL-C/TC that predicted the presence of metabolic syndrome were 80.5 cm, 0.84, 0.61 and 0.34 respectively.ConclusionThe presence of metabolic syndrome among Ghanaian postmenopausal women can be predicted using WC, WHR, TG/HDL-C and HDL-C/TC.

Anti-tumor and chemosensitization effects of Cryptotanshinone extracted from Salvia miltiorrhiza Bge. on ovarian cancer cells in vitro

ETHNOPHARMACOLOGICAL RELEVANCE Cryptotanshinone, a natural compound isolated from the roots of Salvia miltiorrhiza Bge. (Danshen), is a commonly used traditional Chinese medicine to treat high blood pressure in some countries. It has been shown that Cryptotanshinone induces cancer cells apoptosis and impairs cell migration and invasion. However, the antiproliferation and chemosensitization effects of Cryptotanshinone on ovarian cancer and the underlying mechanism are not fully elucidated. AIM OF STUDY In this study, we evaluated the inhibitory effect of Cryptotanshinone on ovarian cancer cells and explored the underlying molecular mechanism. Additionally, the chemosensitization potential of Cryptotanshinone was evaluated in combination with cisplatin. MATERIALS AND METHODS MTT assay was used for cell viability assessment of ovarian cancer A2780 cells treated with Cryptotanshinone and/ or cisplatin. Flow cytometry was used for apoptosis analysis. Wound healing and transwell assays were used for migratory and invasive potential assessment of Cryptotanshinone-treated ovarian cancer cells. Western blot was used to investigate proteins involved in the mechanisms for metastasis and apoptosis. γH2AX immunocytochemistry was used to detect DNA damage in A2780 cells exposed to Cryptotanshinone and/or cisplatin. RESULTS Cryptotanshinone significantly induced ovarian cancer A2780 cells apoptosis by activating caspase cascade. Additionally, wound healing and transwell assays revealed that Cryptotanshinone could suppress migration and invasion of ovarian cancer cells and dramatically inhibited MMP-2 and MMP-9 expression. Furthermore, Cryptotanshinone could sensitize A2780 cells to cisplatin treatment in a dose-dependent manner. CONCLUSION Our data confirmed the anti-tumor effect of Cryptotanshinone on ovarian cancer cells and provided new findings that Cryptotanshinone could sensitize ovarian cancer cells to chemotherapy.

Anti-Tumor Effect of Pinus massoniana Bark Proanthocyanidins on Ovarian Cancer through Induction of Cell Apoptosis and Inhibition of Cell Migration

Pinus massoniana bark proanthocyanidins (PMBPs), an active component isolated from Pinus massoniana bark, has been reported to possess a wide range of biochemical properties. Here, we investigated the anti-tumor effect of PMBPs on ovarian cancer. The results indicated that PMBPs significantly reduced the growth of ovarian cancer cells and induced dose-dependent apoptosis. The underlying mechanisms involved were elucidated to include the loss of mitochondrial membrane potential, down-regulation of the anti-apoptotic protein Bcl-2 and the activation of Caspase 3/9, suggesting that PMBPs triggered apoptosis through activation of mitochondria-associated apoptotic pathway. In addition, wound healing and transwell chamber assays revealed that PMBPs could suppress migration and invasion of ovarian cancer cells. PMBPs dramatically inhibited MMP-9 activity and expression, blocked the activity of NFκB and the activation of ERK1/2 and p38 MAPK. Our findings suggest that PMBPs has the potential to be developed as an anti-tumor drug for ovarian cancer treatment and/ or disease management.

Anti-metastatic and differential effects on protein expression of epigallocatechin-3-gallate in HCCLM6 hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the third highest cause of cancer-related mortality in humans. Epigallocatechin-3-gallate (EGCG) has been shown to inhibit the metastatic activity of certain cancer cells. The aim of this study was to determine the effects and molecular mechanism(s) of action of EGCG in human HCC cells. A migration and invasion assay for the metastatic behavior of HCCLM6 cells was performed. The anti-metastatic effects of EGCG were investigated by RT-PCR and gelatin zymography. A total cellular protein profile was obtained using 2-dimensional gel electrophoresis (2-DE), followed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) analyses of proteins with significant differences in expression following treatment with EGCG. The results revealed that EGCG induced apoptosis and inhibited the metastasis of HCCLM6 cells. The anti-metastatic effects of EGCG were associated with the inhibition of matrix metalloproteinase (MMP)-2 and MMP-9 activity. The expression levels of far upstream element (FUSE) binding protein 1 (FUBP1), heat shock protein beta 1 (HSPB1), heat shock 60 kDa protein 1 (chaperonin) (CH60) and nucleophosmin (NPM) proteins, which are associated with metastasis, were significantly altered in the EGCG-treated HCCLM6 cells. The data from the present study suggest that EGCG has potential as a therapeutic agent for the treatment of HCC.

Prokaryotic Expression, Identification and Bioinformatics Analysis of the Mycobacterium tuberculosis Rv3807c Gene Encoding the Putative Enzyme Committed to Decaprenylphosphoryl-d-arabinose Synthesis

Decaprenylphosphoryl-d-arabinofuranosyl (DPA), the immediate donor for the polymerized d-Araf residues of mycobacterial arabinan, is synthesized from 5-phosphoribose-1-diphosphate (PRPP) in three-step reactions. (i) PRPP is transferred to decaprenyl-phosphate (DP) to form decaprenylphosphoryl-d-5-phosphoribose (DPPR). (ii) DPPR is dephosphorylated to form decaprenylphosphoryl-d-ribose (DPR). (iii) DPR is formed to DPA by the epimerase. Mycobacterium tuberculosis Rv3806c and heteromeric Rv3790/Rv3791 have been identified as the PRPP: decaprenyl-phosphate 5-phosphoribosyltransferase and the epimerase respectively. Rv3807c, however, as the candidate of phospholipid phosphatase, catalyzing the biosynthesis of decapreny-l-phosphoryl-ribose (DPR) from decaprenylphosphoryl-β-d-5-phosphoribose by dephosphorylating, has no direct experimental evidence of its essentiality in any species of mycobacterium. In this study, Rv3807c gene was amplified from the genome of M. tuberculosis H37Rv by PCR, and was successfully expressed in Escherichia coli BL21 (DE3) via the recombinant plasmid pColdII-Rv3807c. The resulting protein with the 6× His-tag was identified by SDS-PAGE and Western blotting. The protein was predicted through bioinformatics to contain three transmembrane domains, the N-terminal peptide, and a core structure with phosphatidic acid phosphatase type2/haloperoxidase. This study provides biochemical and bioinformatics evidence for the importance of Rv3807c in mycobacteria, and further functional studies will be conducted for validating Rv3807c as a promising phospholipid phosphatase in the synthetic pathway of DPA.

Ezrin as a possible diagnostic and/or prognostic biomarker in mice lymphatic metastatic hepatocellular carcinoma in vivo

Hepatocellular carcinoma (HCC) ranks in the top of cancers leading to death. Early diagnosis is the big challenge in the case of HCC. Our in vitro study showed that Ezrin expression in lymphatic metastasis hepatocellular carcinoma (LNM-HCC) was associated with the metastatic rate. Here we aim to evaluate Ezrin expression as diagnostic and/or prognostic biomarker of LNM-HCC in mice. Chinese inbred 615 mice, Hca-F and Hca-P cell lines were used in the study. Histological changes were determined by Hematoxylin and Eosin, while Ezrin expression was assessed by qRT-PCR, western blot, immunohistochemistry, and enzyme-linked immunosorbent assay. Ezrin expression in this study gives credit to our in vitro study which Ezrin expression was positively correlated with LNM-HCC and negatively with Annexin7 (A7) expression. The highest histological changes were observed in high metastatic primary/secondary tumors combined with high Ezrin expression. Ezrin and A7 are higher in total primary tumors than in total secondary tumors (P = 0.0001, P = 0.021), respectively. Ezrin expression was enhanced in Hca-P A7 down-regulated primary/secondary tumors (P = 0.004), whereas, Ezrin expression was suppressed in Hca-F A7 upregulated primary/secondary tumors. Serum ELISA indicated differential expression of Ezrin among the study groups (P ≤ 0.0001). Ezrin expression was higher in NC-Hca-F than NC-Hca-P (P ≤ 0.0001), suppressed in Hca-F A7 upregulation (P ≤ 0.0001) and in enhanced in Hca-P A7 down-regulation (P = 0.0001). In conclusion, Ezrin level may serve as a differential diagnostic and/or prognostic biomarker for high and low LNM-HCC and may be beneficial in the diagnosis of HCC disease.

Functional analysis of serine acetyltransferase from Mycobacterium smegmatis

Serine acetyltransferase (CysE) is involved in L‐cysteine biosynthesis in Mycobacterium, and it is important for the self‐defense mechanism of the bacteria. Mycobacterium tuberculosis CysE (Rv2335) has been identified as a serine acetyltransferase, and it is orthologous to Mycobacterium smegmatis MSMEG_5947. In this study, the MSMEG_5947 gene was cloned, expressed, and identified as a serine acetyltransferase. To investigate the function of M. smegmatis CysE, a MSMEG_5947 knockout mutant strain (M. sm‐ΔM_5947) was generated through homologous recombination. The growth and morphological characteristics of this strain were studied using growth curves and electron microscopy, respectively. M. sm‐ΔM_5947 grew slower than M. smegmatis mc2155. Electron microscopy revealed that the lack of the M. smegmatis CysE protein caused drastic morphological changes. Therefore, deletion of the serine acetyltransferase retards the growth of the Mycobacterium, but serine acetyltransferase expression is not essential for the survival of the bacteria.